I've used this cassette on a hardtail for more than three years and it has seen at least 8000km of use, of which about 1500km were mountain biking (until I got a fully). In all this time, I never felt like this cassette had failed me, and shifting has always been pretty solid (XT derrailleur and shifters), even though the stiffer XT cassette DOES perform better. And though I destroyed 1 or 2 derrailleur hangers, I haven't bent a single sprocket. I'm pretty sure many users (which is why I don't like lending my bike) do not shift properly, and as a result, destroy some part of the drivetrain. Even if I felt like doing mad wheelies during a hard climb, this cassette wouldn't bend. I'm a rather light, but still...

As for the finish: After some time (and 2 winters with road-salt), the cassette looks a bit messy, but the nickel coating is still mostly intact. No complaints here. The chain (XT or Deore level) is going to be a bigger worry for you.
Last week, I ordered a new one, just to realize that the teeth on the old one are still fine and should last for at least another, if not two years.

So all in all, I can recommend this cassette for any use, however, most people will prefer some lighter cassettes with a spider for their aluminium freewheels on more expensive bikes. But for the price, you get an awesome cassette that won't look like an ugly, rusty cone on your rear wheel after some use. (like the HG30 or cheap 7-8spd cassettes)

Weaknesses: bent really bad during a race when I hit a though short climb

Bottom Line:

here is the link to the picture on what happened on a short tough climb.. bent it out pretty bad after just 6 months on the bike.. http://sphotos.ak.fbcdn.net/hphotos-ak-ash1/hs468.ash1/25697_1397241501300_1540132892_31002595_4633159_n.jpg

I weigh 215 lbs and am pretty hard on things, and this cassette has never given me any troubles. Shifts fast and perfect. I have about 50 miles of hard XC rideing on it and about 400 street miles on it and no sign of wear yet. I guess it would help if it was lighter but then I suppose the durability would suffer. I would buy this if you are not super concerned with weight and just want a quality item that will work well for years. I would not buy this if you weigh any or all of your bike on a scale lol